Speed indicator



United States Patent C) 3,164,016 SPEED INDICATOR Robert C. Dinsrnore,Flint, Mich, assignor to Dinsmore Instrument Company, Flint, Mich, acorporation of Michigan Filed Feb. 23, 1961, Ser. No. 91,201 2 Claims.(Cl. 73-182) This invention relates to a speed indicating device forwater propelled craft.

The use of a Pitot tube for speed indication of vehicles moving throughfluid is known. The problem in connection with water vehicles is toprevent destruction of the tube when the boat strikes an obstacle in thewater or when it might accidentally or intentionally be beached.

The present invention contemplates a structure to prevent damage to thespeed indicator from obstructions and contact with other solid objects.

It is an object of the present invention to provide a device whichutilizes the gravity weight of a Pitot tube in addition to an optionalspring for holding it in speed recording position, the device beingreadily movable into a protected well when there is a possibility ofcontact with a damaging object.

Other objects and features of the invention relating to details ofconstruction and operation will be apparent in the following descriptionand claims.

Drawings accompany the disclosure and the various views thereof may bebriefly described as follows:

FIGURE 1, a sectional view through the bottom of a water vehicle showingthe general arrangement of the parts.

FIGURE 2, a front view of the Pitot tube showing the front elevation ofthe parts.

FIGURE 3, a bottom view of the clamp means for the supporting element.

FIGURE 4, a bottom view of an optional device to serve as a protectiveand supporting element.

Referring to the drawings:

The wall of a vessel 10 is shown having an opening 12 in which ismounted an inverted cup or well member 14 having an outside supportingflange 16 which is screwed to the bottom of the boat by screws 18.Suitable sealing gaskets 20 and 22 are provided around the well andabove the flange, the well being located to be in the fluid mediumsupporting the vessel.

A Pitot tube 24 having an L shape has a forward extending arm 26 exposedto the fluid through which the boat is moving in the direction of thearrow A. At the top of the Pitot tube is a flexible tube 28 whichextends through a hole 30 in the well 14. This tube is sealed in thewell and leads to a dial indicator device 32 of the type now used forspeed indication. The portion 34 of the tube which passes through thewall of the well is preferably of metallic nature so that it could bewelded, soldered, or otherwise securely sealed into the wall. Theflexible tube 28 can be a plastic material or rubber which can besuitably secured to the tube portion 34 and to the Pitot tube 24 by aslip fit. It is preferably arranged in a coil in the well. The supportfor the Pitot tube and also guard consists of a substantially V-shapedsingle piece of spring wire or its equivalent in the form of slenderfunicular element of form sustaining nature which is fastened at eachend 36 to the tube 24. The spring then extends downwardly below thePitot tube and outwardly in the wing portions 38 and then forward inguard portions 40 which meet in a bight portion 42 hinged in a smallmounting bracket 44, held to the bottom of the boat by screws 46 forwardof the well 14.

With the construction shown, it will be seen that the Pitot tube wouldbe resiliently positioned below the boat supported by the resilience ofthe coil tubes 28 and guarded by the arms 40 and 38 of the spring guard.Any obstruction striking the guards would move the Pitot tube up intothe well 14 protecting it from injury and the passing of the obstructionwould permit the device to move down into a reading position again.

In FIGURE 4 an optional construction is shown in which the guard arms 50which compare with the guard arms 40 of FIGURE 1 are angled through sideflanges 52 in the supporting bracket 54 in a pivotal relationship at 56.The bight of the arms 50 is formed in a coil 58 which bears against thebottom of the boat to limit the downward motion of the guard arms 50. Ifit is desired to add resilience to the guard arms, the coil 58 can beclamped against the bottom of the boat by a small clamp 60 held by ascrew 62. As shown by the dotted lines, the clamp can be moved out of aposition where a free action is desired on the part of the guard arms50.

The use of the strand or funicular element such as the thin wire for theguard elements avoids any planing effect which would tend to lift thetube out an effective reading area and prevents disturbing ripples orpressures in the month end of the Pitot tube. The light construction ofthe entire assembly balanced against the resilience of the tube coil 28affords stability for the tube with ample protection against damage. Thetube is supported by the funicular or filamentous V-shaped element whichholds it between the general plane of the V and the walls of the vessel.The tube 28 physically associates the Pitot tube with the walls of thevessel and also pneumatically connects the Pitot tube passage to theinterior of the vessel.

I claim:

1. A speed indicator mechanism for water craft which comprises:

(a) means forming in the bottom of said craft a recess open to thesupporting fiuid for said craft and sealed from the interior of thecraft,

(b) a Pitot tube to be suspended adjacent said recess and movable from aposition within said recess to a position below the bottom of saidcraft,

(0) supporting means for said tube comprising a resilient tube in saidrecess mechanically connected at a distal end to said Pitot tube andadapted to be pneumatically associated therewith and with a registeringindicator within the craft on the other end and mechanically supportedat said other proximal end in said recess, said resilient tube having alength bent upon itself and disposed in said recess such that it servesas a resilient expanding and contracting moving mount for said Pitottube to permit the tube to be displaced into the recess or supportedbelow it, and

(d) means to guide and guard said Pitot tube comprising an extendingelement mounted at one end on said craft forward of said Pitot tube andfastened to said Pitot tube at the other end to guide said Pitot tubeinto and out of said recess, said last means depending below said tubeat one portion to protect the \3 tube against contact with foreignobjects in the supporting fluid.

2. A device as defined in claim 1 in which said means to guide and guardsaid Pitot tube comprises a form sustaining funicular element having ashape flaring outwardly and downwardly of said tube to a point below andspaced on either side of said tube and extending up- Wardly andforwardly at an angle to a fixed position on the bottom of said craft.

References Cited in the file of this patent UNITED STATES PATENTS FowlerApr. 1, 1913 Harvey Dec. 30, 1930 Sveudsen Nov. 17, 1931 Harvey Jan 12,1932 Zink Jan. 10, 1933 Diehl June 24, 1941

1. A SPEED INDICATOR MECHANISM FOR WATER CRAFT WHICH COMPRISES: MEANSFORMING IN THE BOTTOM OF SAID CRAFT A RECESS OPEN TO THE SUPPORTINGFLUID FOR SAID CRAFT AND SEALED FROM THE INTERIOR OF THE CRAFT, (B) APITOT TUBE TO BE SUSPENDED ADJACENT SAID RECESS AND MOVABLE FROM APOSITION WITHIN SAID RECESS TO A POSITION BELOW THE BOTTOM OF SAIDCRAFT, (C) SUPPORTING MEANS FOR SAID TUBE COMPRISING A RESILIENT TUBE INSAID RECESS MECHANICALLY CONNECTED AT A DISTAL END OF SAID PITOT TUBEAND ADAPTED TO BE PNEUMATICALLY ASSOCIATED THEREWITH AND WITH AREGISTERING INDICATOR WITHIN THE CRAFT ON THE OTHER END AND MECHANICALLYSUPPORTED AT SAID OTHER PROXIMAL END IN SAID RECESS, SAID RESILIENT TUBEHAVING A LENGTH BENT UPON ITSELF AND DISPOSED IN SAID RECESS SUCH THATIT SERVES AS A RESILIENT EXPANDING AND CONTRACTING MOVING MOUNT FOR SAIDPITOT TUBE TO PERMIT THE TUBE TO BE DISPLACED INTO THE RECESS ORSUPPORTED BELOW IT, AND (D) MEANS TO GUIDE AND GUARD SAID PITOT TUBECOMPRISING AND EXTENDING ELEMENT MOUNTED AT ONE END ON SAID CRAFTFORWARD OF SAID PITOT TUBE AND FASTENED TO SAID PITOT TUBE AT THE OTHEREND TO GUIDE SAID PITOT TUBE INTO AND OUT OF SAID RECESS, SAID LASTMEANS DEPENDING BELOW SAID TUBE AT ONE PORTION TO PORTECT THE TUBEAGAINST CONTACT WITH FOREIGN OBJECTS IN THE SUPPORTING FLUID.